Why is ethanol soluble in water but not propane?

Answer : its about the bonding capacity of the molecule

first of all: water is a polar molecule and therefore hydrogen bonding exist within the molecule.

hydrogen bonding is when hydrogen bond with either flourine, nitrogen or oxygen.

ethanol is a polar molecule and there is a hydrogen bonding within its molecule. However, propane is non-polar molecule and dispersion forces is the only intermolecular force that is exist within its molecule.

Due to similar bonding capacity, ethanol is soluble in water.